What Is Airframe Material Strength Analysis?

As aerospace consultants, we’re always asked ‘What Is Airframe Material Strength Analysis?’. There are multiple ways to approach material strength analysis, especially when it comes to airframes. Airframe materials must attain exceedingly high safety standards and therefore require thorough testing and analysis. For more insight, continue reading this blog.  

Understanding Airframe Material Strength Analysis  

Every airframe component undergoes airframe material strength analysis. The materials used in airframes are not based on ‘what’s available’ or ‘affordable’. The utmost priority is that materials used in airframe design are safe.  

How do you ensure the safety of materials? Airframe materials must be exceedingly durable and enduring. One way to guarantee this is with rigorous testing.

Material strength analysis is a discipline used across almost every engineering project in the aviation industry to grant approval for use.  

Once a material is confirmed to have suitable density, mechanical properties, weight distribution, and environmental tolerance, then it can be used in an application.  

Why Is Airframe Material Strength Analysis Necessary?  

The materials used in airframe design must endure immense pressure, hostile environments, and extreme temperatures. The external environment impacting aircraft could cause severe damage to notwithstanding materials, whether the jet is taxiing, in take-off, cruising, or descending. 

According to The Airliner Cabin Environment and the Health of Passengers and Crew, outside temperatures impacting aircraft can reach below -55°C or above 50°C. Ambient pressure can range from 10.1 kPa to 101 kPa (kilopascal). Water content conditions can go from virtually dry to greater than saturation.  

Even when an aircraft is not in flight or weather conditions are admirable, there are still stresses affecting airframe materials that could impact performance and safety. 

For aircraft to be certified as airworthy and safe to operate, it must be equipped to withstand these immense fluctuations in environmental conditions. From the preliminary design of airframe components to design completion, all elements must be carefully considered, tested and analysed for suitability.  

Innovation In Material Selection & Analysis For Airframe  

Due to the high risks associated with aviation, materials used must meet meticulously high standards, to be considered suitable for airframe applications.  

Everything in airframe design is therefore intricately complex; we must master our engineering capabilities and industry innovations to bring forth superior products.  

We exist in a technological era that makes achieving safe airframe designs more achievable. Now, airframe engineers can combine hand calculations with MATHCAD computation, Excel Spreadsheets, and PYTHON scripting to assess the strength of materials faster and more accurately.  

What Is Airframe Material Strength Analysis? A Comprehensive Guide  

1. Material Selection  

Different airframe components will require different material properties. Identifying the requirements for an airframe component, in terms of strength, stiffness, fatigue resistance, moisture resistance, corrosion resistance, and weight is the first step for engineers.  

Airframe engineers must then source materials that match the specifications. Challenges at this stage may occur based on the cost of materials, availability, and manufacturability. Materials must also meet industry standards and regulations.  

2. Load Analysis  

Load analysis is critical for airframe engineers to assess the different forces, stresses, and torques applied to components, structures, and/or materials. To further grasp material strength requirements, three types of load analysis are conducted- 

• Flight Load Analysis- Calculates the loads aircraft will endure throughout various flight conditions.  

• Ground Load Analysis- Determines the loads impacting aircraft during non-flight conditions.  

• Environmental Loads- Considers the fluctuations in environmental factors, such as temperature, moisture, pressure, and aerodynamic forces.  

For more information on types of loads and stresses, read our blog Exploring Stress Analysis Of Aircraft Components. 

3. Structural Analysis  

Specialists will analyse an airframe’s structural integrity throughout every design stage and beyond. This again ensures pre-operation airworthiness, as well as airworthiness throughout the aircraft’s lifespan.

When maintenance is conducted or modifications are made to an aircraft, clearly defined processes must be adhered to, so its safety and reliability are not compromised. Read more about the structural evaluation of aircraft changes here.  

Approaches to structural analysis may include- 

• Finite Element Analysis (FEA)- Simulates the load conditions on a detailed, computerised model, determining stress distributions and potential weak points.  

• Stress Analysis- Calculates the different stresses impacting parts of the airframe structure under various load conditions.  

• Buckling Analysis- Assesses the possibility of buckling under compressive loads, especially for slender structures, such as wings or fuselage skins.  

4. Fatigue And Fracture Analysis  

The majority of commercial aircraft have a lifespan of about 30 years and are designed for roughly 30,000 cycles. The airframe materials must be able to maintain their high performance, not just once, but repeatedly.  

• Fatigue Life Estimations- Determines the fatigue life of aircraft by analysing performance throughout repeated loading cycles.  

• Fatigue And Damage Tolerance– Identifies possible damage to an aircraft in the form of cracks, and predicts how cracks will grow, and their impending impact.  

5. Thermal Stress Analysis  

Thermal pressure on materials can cause structural changes, both physically and atomically. Not only does this jeopardise the performance of a singular airframe component, but the entire aircraft.  

• Thermal Stress Analysis- Evaluate how different temperatures, at all extremities, impact materials, especially for high-speed or high-altitude applications. 

• Thermal Fatigue- Analyses how many thermal cycles a material can endure before succumbing to material fatigue.  

Material Strength Analysis With Airframe Designs  

We hope this blog answers your query, ‘What is Airframe Material Strength Analysis?’. 

At Airframe Designs, we specialise in analysis at all stages of the design process. Whether you require our input during the conceptual design of an airframe or the final design calculations to be submitted for certification, we can help. Read more on our analysis capabilities here.  

If you would like to see examples of our work, follow this link to our case studies.  

If you would like more information on ‘What is airframe material strength analysis?’ or would be interested in partnering with us for your next project, contact us today.